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LIBRARY OF CONGRESS, 



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UNITED STATES OF AMERICA. 



GENERAL INSTRUCTIONS 



REARING SILKWORMS, 



TREATISE OH 2MINS HEALTHY SILKWORM EOOS, 



Sketch of the Habits and Structure of the Silkworm. 



By / 
MRS. LOUISE RIENZI. 




SACRAMENTO: 

STATE OFFICE : : : P. L. SHOAFF, SEPT. STATE PRINTING. 

1887. 



5 re 

/R5 5 



Entered according to Act of Congress, in the year 1SS7, 

By Mes. Louise Eiekzi, 

In the Office of the Librarian of Congress, at Washington. 



GENERAL INSTRUCTIONS 

FOR 

REARING SILKW0R" 



For every ounce of eggs it will require about 
seventy-two yards of space to rear the worms dur- 
ing the fourth stage. Racks can be used having 
many tiers of shelves. The first shelf should be 
about two feet from the ground, and the shelves 
about twelve or fifteen inches apart. 

To disinfect or render pure the air in cocooneries, 
chloride of lime should be used. Dissolve a quan- 
tity of lime in eight times its volume of water, and 
leave this in the room for a short time. 

The worms from an ounce of eggs will consume 
from twelve hundred to thirteen hundred pounds 
of mulberry leaves. The leaves must be healthy, 
vigorous, ,and of a nutritive quality. The worms 
must never be fed with leaves wet with dew or rain, 
as damp or wet leaves are very injurious to silk- 
worms. It breeds disease. 



4 General Instructions for 

Light is a necessary element of life, but the direct 
rays of the sun should never be allowed to fall on 
the silkworm. 

Pure air is even more indispensable than light, 
for respiration. It prevents the bed, or refuse of 
leaves, from fermenting. Caution should be taken 
not to allow the bed of refuse leaves under the 
worms to ferment, as this is the cause of all the 
diseases which silkworms are heir to. 

The air should be continually renewed, not by a 
direct current, but insensibly renewed by means of 
an open window or door. 

Cocooneries should be kept at an even tempera- 
ture, night and day. 

It will take about six days for the worm to pass 
from one moulting stage to the next moulting, ex- 
cepting after the fourth moulting, when it takes 
from nine to ten days for the worm to mount to the 
brush to spin its cocoon. 

If the season when rearing silkworms should be 
damp, from rain or other causes, have small pieces 
of unslaked lime in the corners of the room. The 
lime will absorb dampness. Also, powdered char- 
coal, sprinkled on the under leaves of trays where 
worms are, will prevent the leaves from moulding, 
and will render the odor of the old leaves less pun- 
gent. 



Rearing Silkworms. 



Fig.i. From an ounce of eggs 

hatching will be completed 
P in the space of three days. 
Care should be taken to 
keep each day's hatching 
separate, in order that the 
worms will moult at their 
respective periods. The 
approach of the time for 
hatching may be perceived 
by the eggs becoming of a 
pale lavender color, when 
small-sized pieces of per- 
forated paper or bobinet should be placed over 
them. When the worms begin to make their ap- 
pearance place mulberry leaves over this covering; 
and as the worms 
cling to them, re- 
move the leaves 
with the attached 
worms from the 
receptacle where 
the eggs have been, 
and place them 
in the position 
shown in Figure 1. 
Eggs will generally 
hatch in the morn- 
ing hours; but if 




6 General Instructions for 

any should be delayed until the afternoon, place 
them between the rows of leaves, as is shown in 
illustration No. 2. At first the worms must be fed 
every two or three hours with fresh mulberry leaves, 
which should be cut into small shreds, about a 
quarter of an inch wide. Though the leaves that 
are given to the worms should not be all consumed, 
it is very necessary that they be renewed every few 
hours, as the worm constantly requires fresh food. 
During the moulting stage the worms should not 
be given any food; and after moulting the feeding 
should be so directed that one worm will not become 
stronger than another. With the proper tempera- 
ture, and the requisite attention in feeding, the 
moulting stage will be passed in six days. 

When the worm issues forth from the egg, its body 
assumes a chestnut color, and its head appears of a 
shining black. By the third day the body has be- 
come darker, and the head almost whitish. On the 
fourth day the body is of a yellow waxy appearance; 
and on the sixth day, if the worm be looked at be- 
tween the eye of the observer and the light, it seems 
a clear, transparent, waxy substance. 

During the first four days the leaves should be 
given to the worms every two hours, and the last 
meal in the evening should be given as late as is 
convenient, and more abundant than the morning 
meal, which should be given as early as possible. 



Rearing Silkworms. 7 

First Stage of Silkworm. 

Silkworm, first day. 

Silkworm, second day. 

Silkworm, third day. 
J ^^^- Silkworm, fourth day. 
**^S£L. Silkworm, fifth and sixth days. 

In placing the leaves upon the worms they should 
be put first around the edges, in order that the worms 
may not heap themselves up in the middle of the 
trays in their effort to get at the fresh food. In the 
early stages, as has been said before, it is necessary 
to cut the leaves into shreds, that the young worms 
may have a better opportunity to feed, and that they 
be administered every two hours. In the last two 
days of the first stage, the leaves should be given in 
less quantities at the regular times of feeding, as at 
that time the worm loses some of its appetite. 

The approach of the moulting period may be ob- 
served from the fact that the worm remains immov- 
able, with its head erect. When it is about to throw 
off its old envelopment, it moves its head about, and, 
with a vermicular movement, struggles forth. Care 
should be taken not to disturb worms during the 
moulting period, for the reason that before going 
into this state they exude a gummy substance, also 
fine web-like threads, which cling to their surround- 
ings, and enable the worm to liberate itself from the 
old skin. If there be any worms which have not 



8 General Instructions for 

passed the moulting stage, those already moulted 
should not be fed until all have passed the stage. 
After moulting, the worms are generally very much 
fatigued and have not much appetite, being able to 
go without food for sixteen or eighteen hours with- 
out injury to themselves. 

The cocoonery should be kept at a temperature 
ranging from sixteen to seventeen degrees Reamur, 
or nineteen to twenty degrees Centigrade. There 
should also be light and air in the cocoonery. 

In the early stages the worms can be changed from 
one tray to another, by using mosquito nettings, by 
putting the latter over the tray containing the worms 
to be transferred, and on this netting fresh cut mul- 
berry leaves. The worms, attracted by the fresh 
leaves, will crawl through the openings, and maybe 
taken to a fresh tray in a few hours. The old leaves 
are then worthless, and should be thrown away, and 
the tray should be aired before it is again used. 
During the first stage the worms should be changed 
to clean trays twice. In the second stage, for the 
first two days, feed them every two hours ; during 
the second two days, sparingly; during the following 
two, more abundantly; and in the last two, very 
lightly. In six days, with proper care and tempera- 
ture, the worms will pass from one stage to another. 
After the first moulting, its body becomes of a dark 
gray color, which changes to a yellow waxy hue 



Rearing Silkworms. 



9 



when about to enter the second stage of the moult- 
ing. 

Second Stage of Silkworm. 

Silkworm, first day. 
Silkworm, third day. 
Silkworm, fourth day. 
Silkworm, fifth and sixth days. 

Eight hours after having moulted the second time, 
the worms should be placed on a clean tray by the 
method before explained. Precaution should be 
observed in taking care that the room has always a 
good supply of fresh air, and is well ventilated. As 
the worms increase in size, their respiration and 
transpiration also increase with their growth. The 
worms should always be kept so that they can eat 
comfortably, and without crawling over one another 
in their search for food. 

Third Stage of Silkworm. 
Silkworm, first day. 

Silkworm, second day. 

Silkworm, third day. 

^^ Silkworm, fourth day. 

Silkworm, fifth and sixth days. 




10 



General Instructions for 



After passing the third stage they will require a 
much larger area, the worms from one ounce of eggs 
requiring a space of seventeen square yards. A 
number of trays can be made to occupy a small 
space, by placing them according to the Cavallo sys- 
tem, upon a rack one over the other, leaving suffi- 
cient spaces intervening. Thus they can be moved 
easily, fed, and attended to. Such an article could 
be made of laths, placed horizontally on four per- 
pendicular uprights. The space between shelves 
should be about one foot. Racks can .also be made 
as per illustration. 




.^p*' 



In this the frame is covered with tacks partially 
hammered in, to which cords are attached, running 



Rearing Silkworms. 



11 



across the frame in both directions, and forming 
squares at intersections less than one inch apart. 
When this is done, the tacks can be hammered 
home, which will keep the cord firmly in place. 
These racks may also be used for changing the 
worms. These frames may be made any size to suit 
the rack; three or four frames may be made to suit 
the length of the shelves of rack. 




Tray for Each. 

When the worms have passed through the third 
moulting they should be again changed, as they 
were at the conclusion of the second moulting. 
Their bodies at this period is of a grayish-yellow 
color, and the skin of the neck and head is much 
wrinkled. After the third moulting the worms 
should be- changed every two days, and also changed 
just previous to moulting, in order that they may 
have clean beds to moult on. The temperature of 
the room in which the worms are reared should be 
sixteen degrees to seventeen degrees Reamur; and 
if the weatherjis very hot the apartment may be 



12 



General Instructions for 



cooled by placing basins of cold water in the room, 
and sprinkling the floor with cold water at intervals. 

Fourth Stage of Silkworm. 



Silkworm, first day 



Silkworm, second day. 




Silkworm, sixth day. 



During this last stage the brush should be pre- 
pared on which the worms may spin. Mustard and 
asparagus seed stalks can be conveniently used for 
this purpose as brush bouquets, to which the worm 
can attach threads and form cocoons. Dried chap- 
arral branches can also be intermingled with the 
mustard and asparagus, as in the illustration. Air 
should be allowed to circulate freely through the 
mass. The brush bouquets should be put in the 
frame fan-shape, and then bent over to form the 
arch, 



Rearing Silkworms. 13 




Illustration No. 0. 

The fourth moulting stage is the most perilous the 
silkworm has to pass through, and requires a period 
of about six days from the last moulting. The worm 
should not be removed from the tray before sixteen 
hours after moulting have elapsed. As they do not 
all pass through it at the same time, extra care 
should be observed. Leaves may be administered 
whole at this time, and twigs, as the worm has at 
this period a voracious appetite. It should be ob- 
served at this point that no dew or rain should be 
present on the leaves. After the fourth moulting 
the worms will remain for nine or ten days before 
they are ready to spin. The worms will eat an 
enormous quantity of leaves, and should not be 
crowded on the trays, which should be only about 
two thirds full, in order to give the worm plenty of 
room as it increases in size. During this stage the 
worms should be changed to clean trays every other 
day, and every day if possible. 



14 



General Instructions for 

Fifth Stage of Silkworm. 




Silkworm, seventh day. 



Rearing Silkworms. 



15 



The worms will occupy from three to four times 
the space they occupied at their moulting. 

The worms need more air and ventilation at this 
period, and an infraction on this rule would be fol- 
lowed by grave results. After the fourth moulting 
the temperature must not exceed sixteen degrees 
Reamur, but may fall below to any degree, as after 
this the worm is not so subject to cold, but would 
suffer greatly from too much heat. 




Worm Ready to Spin Cocoon. 

When mature and ready to spin, the silkworm 
stops eating, and appears of a golden, transparent 
color. They wander over the mulberry leaves with 
heads raised, as if seeking some suitable place. 
When the worm begins to spin only the seric and 
animal substance constitute the body, which becomes 
perceptibly smaller. When two thirds of the worms 
have mounted the brush those remaining should be 
removed to another tray, that they may not be dis- 



16 



General Instructions for 



turbed by those already mounted. By feeding them 
well they will soon be able to mount like the rest. 
The brush arches, as per illustration No. 9, should 
be placed on the trays, and if not convenient enough 
for the worms to mount a few branches should be 
added. Worms unable to get up should be gently 
assisted to a favorable position, whence they may 
crawl up themselves. A free current of air is indis- 
pensable at this stage. It will take four days to 
finish a cocoon, which should be removed from the 
brush eight to ten days after haying been. first spun. 
The chrysalis in the cocoon can be stifled by ex- 
posing the cocoon to the hot sun for three or four 
days, or the cocoon may be placed in an oven of 
moderate temperature, and in fifteen or twenty min- 
utes the desired object will be accomplished. 





Chrysalis, Lateral View. 



Chrysalis. 




Rearing Silkworms. 17 

An ounce of eggs will produce one hundred to one 
hundred and twenty-five pounds of fresh cocoons, if 
worms are well fed and care taken of them. 

Silkworms well fed will form their cocoons in 
about three or four clays from the time they com- 
mence to throw out the floss silk. The cocoons 
should be gathered from the brush the eighth or 
tenth day from the day the worm first commenced 
to spin. The moth will pierce through the cocoon 
from the seventeenth to the twentieth day. In 
reserving cocoons for propagating from always 
choose the firmest and most perfect ones. The dura- 
tion or existence of the moth is from ten to fifteen 
days. They do not eat during this stage, as the 
moth does not possess digestive nor nutritive organs. 
Moths should be kept in a dark room, as the light 
acts as a stimulant upon them. The moths gener- 
ally come forth from the cocoon during the morning 
hours. As soon as they are coupled they should be 
gently lifted, by taking hold of the wings of both, so 
they may not become separated, and placed in a tray 
covered with cheese cloth or other light fabric. The 
moths are to remain coupled about six hours. If 
the moths do not separate spontaneously after six 
hours conjunction, the male should be separated 
gently from the female, by taking the wings of the 
moths between the thumb and second finger, and 
with the first finger of both hands carefully separate 
one from the other. The female should be placed 



18 General Instructions for 

in a cell or sack made out of crinoline or muslin, 
where she can lay her eggs. The male can be kept 
until next day, and if there are a greater number of 
females than males, then the males can be used to 
couple again. 




Male Moth. 

In selecting moths for propagating, one should 
note the following directions: 

That healthy moths come out of cocoons between 
six and ten o'clock in the morning. 

That healthy moths are of a pale white color, and 
their wings dry rapidly and are well spread out. 

The male moth can be distinguished from the 
female as it has two black signs or lines on its wings. 
The male is generally smaller than the female. 

If the eggs laid are abundant and equal in size, of 
a violet color, and the precautions mentioned have 
been taken, then the product may be considered 
good. Discard all eggs that remain of a yellow color 
after the fifteenth day from the time the moth laid 
them, as they will not hatch. Do not propagate 
from moths that are not vigorous, nor from those 



Rearing Silkworms. 19 

that appear swollen and have, subcutaneously, a 
yellow fluid substance between the rings of their 
abdomen. 

Those moths having reddish marks on their abdo- 
men, or those evacuating a white or black substance, 
are not healthy moths, and in consequence should 
be destroyed. 

After forty-eight hours the cloths or sacks upon 
which eggs are laid should be hung up in a cool dry 
place, away from the reach of mice or rats, so as to 
preserve them until the next season. 




Female Moth Laying Eggs. 



20 Treatise on the Selection of 

TREATISE 

ON THE 

Selection of Healthy Silkworm Eggs, 



It is well to understand in the beginning that the 
two diseases, pebrine and appoplesia, to which silk- 
worms are subject, are entirely distinct from each 
other, both in their causes and effects, and in regard 
to external and internal symptoms in the insects. 

The disease pebrine was first discovered to exist 
among silkworms at Provenza in 1840; in 1845 it 
appeared at Covailinni; in the following year at 
Avignone, and at Nimes in 1849; in Bucluza and the 
valley of St. Martin in 1852, and in Spain during the 
same year, and in the next year, 1853, at Benaco; in 
Berne and in the Tyrol in 1855. Thence it extended 
to European and Asiatic Turkey and India in 1859. 
In 1858 the silkworm eggs in Prussia were infected 
at a time when similar disturbing causes were found 
among the establishments of silk culture in Tuscany, 
Italy. Switzerland was attacked in 1860; two years 
afterwards it is found at Bucharest, and in 1864 at 
Capazzi, but up to the present Portugal has fortu 
nately escaped molestation. 



Healthy Silkworm Eggs. 21 

Pebrine is a fungoid disease, better known under 
the term "corpuscular parasites." It is one of the 
greatest enemies to the silk culturist, and propagates 
itself with remarkable rapidity. It was thought for 
a long period of time that these fungoid corpuscles, 
so called, were but an organized substance, not inde- 
pendent organisms. Later investigators, however, 
among whom Professors Haberlandt and Pasteur 
may be particularly mentioned, have demonstrated 
that they are actually independent organisms. 
Without treating the subject at length, or wearying 
the reader with minor details, the writer will limit 
the description of the disease in the insect to the 
appearance of the corpuscles and an analysis of the 
development of the fungoid parasite. 

In the first place, it has been satisfactorily ascer- 
tained that the parasite lodges in the fluid of the 
egg; also, adhering to its external part, viz.: the 
shell. It is always present in all the organs of the 
infected worm, as also in the blood, muscles, and 
silk glands of the alimentary canals. In the single 
organ of the chrysalis they are found to be very 
abundant. In the moth affected the corpuscles are 
found especially in the membraneous folds of the 
wings, the eyes, and in the open spaces of the feet. 
They are also found in the ovaries of the female. 
These oviform fungoid are possessed of great tenacity 
of life. In a dry or petrified state they are imper- 
ishable; and even when placed in distilled water by 



22 Treatise on the Selection of 

Professor Lebert, where they were kept many years, 
they were found to be unaltered. Neither alcohol 
or acids can affect them to any perceptible degree, 
the latter producing but a slight paleness of the 
corpuscles. Our only recourse, therefore, in destroy- 
ing a germ of disease so indestructible, yet so de- 
structive, is to burn up all matter infected with their 
presence. 

It may, therefore, be readily perceived how dan- 
gerous a disease is this petechia, or pebrine (which 
is known scientifically under the name of "ovoidali 
corpusculis "), in the silkworm, in the form of the 
egg, worm, chrysalide, and moth. 

In order to obtain satisfactory results in the rear- 
ing of silkworms, and insure the production of their 
quota of silk, it is absolutely necessary that the 
worms be in a healthy condition. As early as the 
year 1857, Dr. Osimo, of Padua, had discovered the 
existence of " microscopi corpuscules" in silkworms, 
infected with pebrine, and he declared them to be 
" algor unicellular." We are indebted to the scientist 
Dr. Charles Vitaldini for the discovery of corpuscles 
existing in the eggs of the worm. Later many other 
eminent microscopists verified this discovery, among 
whom were Frederick Haberlandt, Emilio Coma, B. 
G. Cavallieri, Professor Cantoni, and Professor Pas- 
teur. 

The method by microscopical inspection is the 
only one available in discovering the presence of 



Healthy Silkworm Eggs. 23 

this pest, which, if not checked in time, will destroy 
a whole crop. Professor Pasteur recommends the 
following method of finding whether the corpuscle 
exists: It is to take a couple of cocoons you would 
use for reproducing eggs, and subject them to a high 
temperature— for instance, thirty degrees Reamur — 
and by this means hasten their transformation into 
the butterfly or moth. Then inspect, microscopic- 
ally, the blood of the moth. If it is found, on 
examination by the microscope, that the blood con- 
tains any ovoidal corpuscles, they should not be 
used for propagation, but the cocoons be turned over 
for silk reeling, and thus made use of. If no ovoidal 
corpuscles be found, the cocoons are perfectly healthy, 
and may be used for propagating purposes. The 
writer, however, does not favor this way of testing 
the condition of the cocoons, although recognizing 
the great ability of Pasteur. 

Forcing nature to do its work hurriedly by means 
of artificial heat, in her estimation, is inferior to the 
processes of nature. It is clear that the blood of 
the insect, subjected to this high temperature, must 
undergo a physical change, and would in all prob- 
ability suffer therefrom. A better method is that pro- 
posed by Sig. Felice Franchesehini, a distinguished 
silk culturist of Italy. It is substantially as follows: 
Instead of using artificial heat for forcing the meta- 
morphis of the chrysalis, take a sample of cocoons, 
six or eight days after they have mounted the brush 



24 Treatise on the Selection of 

to spin, from those which you wish to keep for seed, 
selecting some from all stages of completeness. Let 
some be those cocoons that were first spun, others 
not in so advanced a stage, and still others late in 
their operations. Then, with a pair of scissors or a 
sharp penknife, cut open the cocoons,- extracting 
therefrom the chrysalis. With the same instrument 
cut open the abdomen, beginning at the lower part 
and extending the incision upwards. This is a 
simple operation, and may be performed by any 
one, as it is of no consequence if the cuticle be in- 
jured in the operation. Care must be taken to select 
the female chrysalis for this experiment, for in its 
abdomen lie the eggs, which may by a little practice 
and patience be extracted from the ovary tubes. 
Then, having isolated the eggs, wash them well in 
pure water, and they are ready for the microscopical 
examination. If they are found, upon inspection, 
to be free from corpuscular infection, prepare the 
whole crop of cocoons for reproduction and propa- 
gation. But should there, on the other hand, be 
found any traces of infection present, there is still 
time to send the cocoons to the filature in as good a 
state for reeling, because the moth would not have 
gnawed its way out of the cocoon. 

Another method of determining the absence of 
this disease in the moths is by subjecting some of 
the blood of the chrysalis to microscopical examina- 
tion, in order to see if corpuscles be very scarce, or 



Healthy Silkworm Eggs. 25 

entirely absent. The microscope used for examin- 
ing eggs and blood of chrysalis should have a power 
of magnifying from 500 to 600 times. The following 
is the method: On a glass slide put three or four 
eggs, which should be broken by pressure. A drop 
of water should then be added, and from the dense 
and turbid mass the eggshells should be removed. 
This being done, spread the mixture well upon the 
glass, and cover it with another glass slide. In this 
manner the material is fit for the microscope. 

If it be found, on examination, that the mass pre- 
sents the appearance shown in Figure I aa — thus: 
granulations of the yolk in a spherical shape, and of 
variable size, isolated or united in groups — then the 
eggs are free from infection or disease. 

If, however, on the contrary, the eggs are diseased, 
the matter will present the appearance seen in Fig- 
ure II aa, where are represented oscillating semi- 
ovoidal corpuscles, mixed with granulations. 

To examine the blood of the chrysalis, which is the 
yellow liquid we find in its body, put a drop of it on 
the microscope's glass slide and allow it to remain 
so for twenty-four hours. At the expiration of this 
time cover it with another slide of glass, and being 
so covered, place it for inspection. If it be infected 
with disease, ovoidal corpuscles will be perceived, as 
in Figure IV bb; if the blood is free, then it will ap- 
pear as in Figure III aa. 

2 



26 'Treatise on the Selection of 

Extreme cleanliness and care must be observed to 
prevent disease or contagion ' in silkworms. The 
enormous loss of silkworms by pebrine and other 
diseases, and in consequence a diminution of the silk 
crop, may be attributed to the combined effects of 
bad and scanty food, want of sufficient light and 
ventilation; also, to a high temperature and con- 
stant interbreeding of debilitated stock. The dis- 
eases silkworms are subject to are not spontaneous, 
but are immersed into the organisms of the worms 
from the air or from damp or unhealthy leaves they 
may have eaten. 



Healthy Silkworm Eggs. 



27 



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The Silkworm. 



THE SILKWORM. 




The silkworm is a grub or caterpillar of the but- 
terfly called bombyx mori. It comes forth from an 
egg the color of ash wood, and of the form of a lentil, 
somewhat hollow in both surfaces. It is not exactly 
circular, but slightly oval. The pointed part of the 
egg has a little mark or indentation, called by natu- 
ralists micropyle. Under this mark or indentation 
one finds the head of the worm, and near which the 
worm gnaws an elliptical hole in the shell from 
which it emerges. These eggs are deposited by a 
nocturnal butterfly. 

After the fatal disease infested the worms in Italy, 
several varieties of silkworm eggs were introduced 
into Italy. The most important variety were those 
received from Japan. The eggs of the Japanese 
annuals, white cocoon, are much smaller than the 
Italian variety. They present a violet color, with a 



The Silkworm. 29 

tendency towards blue. The eggs, from which the 
worms form a green or sulphurine colored cocoon, 
are olive colored; and those of the yellow cocoon, 
the eggs are a pale green color. 

This grub or insect, which springs, like many 
others, from a nocturnal butterfly, does not present 
itself like other animals on first coining into life, so 
developed and formed that it already corresponds 
perfectly to the small parts of the animal in adult 
age, but in the course of thirty or forty days changes 
three or four times its skin; afterwards it incloses 
itself in a cocoon, a species of ball of oblong form. 
The cocoon serves to defend it from the atmospher- 
ical vicissitudes and from animals, whilst, as a worm, 
-after having moulted or shed its skin for the last 
time, it transforms itself into a chrysalis or nymph. 
In the first few hours of the transformation it is 
enveloped in a skin the color of soft gold ; afterwards 
it takes a brownish tint; then, particularly along 
the length of the back, it becomes hard and shelly. 

It lives in this state a few days, having broken the 
membrane; after having transformed itself into a 
butterfly, or moth, it pierces through the cocoon and 
issues forth from its custody; it then lives without 
food, and only for the multiplication and propaga- 
tion of its species. The female lays her eggs, then 
finally she dies, as well as the male, having performed 
the duties for which they were created. The eggs, 
from which issues forth the silkworm, were first 

2* 



30 The Silkworm. 

taken from China in the year 552 of the era Volgare, 
by two self-styled monks of the order of St. Basilio. 
It was rigidly prohibited to export silkworm eggs 
from China, and to elnde the vigilance they hid 
them in the hollow of a cane, which apparently 
served as a staff. When they arrived at Constanti- 
nople they presented them to the Emperor Gustine 
Justinian. Afterwards they were introduced into 
Greece, Spain, France, and finally into Piedmont, 
Italy. Before the dominant disease affected the 
silkworms, only two special races of silkworms were 
reared in Italy, viz.: those of the race of yellow 
cocoon and those of the white cocoon; and since 
the disease infected the worms they have and are 
now rearing the Japanese race, which we will desig- 
nate as the sulphur-colored cocoon. 

The variety which 'is preferable to rear are those 
worms which moult four times. As regards the 
preference of races of the white cocoon and the sul- 
phur-colored cocoon of Japan, the opinions vary. 
In France, the preference is for the first; in Italy, 
for the second. According to my mode and opinion, 
Italy has reason to give preference to the race of 
sulphur-colored cocoons. 

The silkworm cannot be reared in every country, 
or in every region; but only m those countries where 
the mulberry tree vegetates and grows in the open 
air. The worms could be fed with the leaves of the 
Madura Aurantiaca (osage orange, a tree peculiar to 



The Silkworm. 31 

America), also with the leaves of the tragojiogon pra- 
iense; but from the branches of the first it would be 
very difficult to gather the leaves on account of the 
thorns. As regards the latter, we would have to 
have fields planted, exclusively cultivated, of the 
above variety, to satisfy the appetite of the voracious 
seric insect. Moreover, it has been observed that 
although the silkworm will feed on the same, so soon 
as one administers to them the mulberry leaves they 
will no longer eat the other. It is necessary to ob- 
serve that we must in rearing silkworms proceed to 
follow as near as possible their mode of living in 
their natural state. To nourish them with whatso- 
ever verdure would be quite contrary to their nature, 
because the silkworm was made to live on arborous 
plants, and not on herbaceous plants. 

Even with us, as originally in China, the silkworm 
could be reared out of doors, on the mulberry trees, 
because they are robust and resist without suffering 
cold, heat, the rains, and wind; but abandoning them 
to the trees, they would not yield that profit which 
one would gain by rearing them indoors. 

First — Because the worm out of doors has many 
enemies to combat with: birds, chickens, bats, ants, 
mice, and lizards. 

Second— Then sudden rains or heavy winds might 
precipitate them to the ground, and very soon they 
would be devoured by the ants and other insects; 
therwise, if the ground were dusty, this, penetrat- 



82 The Silkworm. 

ing into the innumerable pores of their skin, would 
be the inevitable cause of a painful death. 

Third — Then, when a greater number of worms 
were on a tree than there were leaves sufficient to 
nourish them with, some, for want of food, would 
die; others, having only had an insufficient quan- 
tity of food, would form a thin membranous cocoon, 
and only the most robust ones would succeed in 
making a perfect cocoon. 

Therefore, rearing the silkworms in houses as we 
do now, and as the Chinese also do at the present 
time, they are secure as far as their enemies are con- 
cerned, also from the intemperate weather. Then 
they are not allowed to want food, as it is adminis- 
tered to them when necessary. They all live, all 
form a perfect cocoon of greater fineness and weight, 
and one can conserve better their own species. 

It is very easy to rear silkworms in houses, they 
having that precious quality — which is not peculiar 
in all grubs— to only move a short distance from 
where they are placed. 

The appearance of the silkworm after it has 
emerged from its shell is a tiny worm with six rows 
of hair in small tufts, of a dark chestnut color, 
namely, two on the back, two near the respiratory 
organs, and two scarcely above their little paws. 

It is only after the silkworm has moulted the 
second time can one distinguish from the appear- 
ance of the worm the color of the cocoon it will 



The Silkworm. 33 

make, viz. : if the worm appears white, or inclined 
to black or striped, with their little paws white or 
yellowish, then, in the first case, the cocoon will 
be white or sulphur-color; in the second, a yellow 
one. So soon as the silkworm emerges forth from 
its shell its length is about three millimetres (i of 
an inch), its diameter seventy-five parts of a milli- 
metre (.75=-3 1 o inch), its weight one hundred and 
seven parts of a gramme ( T ^y gram.) When the 
worm has reached its full development after its 
fourth moulting, its length is seventy-one milli- 
metres (nearly 2i inches), its diameter about the 
fifth ring is seven millimetres (i inch), and its 
weight a little over three grammes.* 

(The following illustration will show the confor- 
mation of the head: A, the mouth; B, the superior 
lip; C, the inferior lip; DD, the jaws formed like a 
saw, which move horizontally in gnawing the 
leaves; EE, the two major feelers; FF, simple eyes, 
six on each side; the head, of a reddish color; these 
eyes are immovable; CC, the minor feelers; II, 
digests the thread of silk which remains in the 
middle; II, the filler a from which the worms spin 
the cocoon.) 

* Note.— The above statistics of weight and measurement, which 
I think exact, have been taken from a compendious table by Prof. 
Haberlandt, which bears the title of " Die setichenartige Kranheit der 
Seidei iranpen- Vienn a . " 



34 The Silkworm. 




The head of the silkworm is composed of horny, 
hard, and rigid parts; the conformation of its head 
is irregular, its two jaws are formed like a saw, 
which move horizontally when gnawing the leaves; 
the two major feelers on each side of the head are 
put in motion every time it has need to feel or 
touch the surrounding particles or objects; the 
worm has twelve eyes, six on each side, of hemis- 
pherical form, immovable, and of a dark red color. 
Ordinarily the real head of the silkworm is mis- 
taken sometimes for the snout; also, some persons 
imagine that the eyes are those two black arched 
spots placed at equal distance in the first ring back 
of the real head; then others maintain that the 
silkworm has no eyes. The body of the silkworm 
is of a lengthened form, almost cylindrical, and is 
divided into twelve rings, with distinct grooves 
between each ring; the same approach and with- 
draw, according as the worm contracts and relaxes 



The Silkworm. 35 

itself. The first three of these rings, not very dis- 
tinct one from the other, compose properly the 
thorax or breast. 

The other nine rings, less voluminous than the 
other three, compose the abdominal parts; the 
eighth ring has a sharp pointed horn on the point. 
The ninth ring is different from all the others, 
because it terminates into three small wings, and 
underneath these, between four small tubercles, 
two on each side, is to be found the anus. Along 
the length of the body of the worm, and properly 
underneath the skin, one discerns a dark streak; 
this is the dorsal vessel; it corresponds to the heart, 
and it continually dilates and contracts alternately. 
This pulsation is more noticeable after the worm 
has reached its greatest size. 

The silkworm has sixteen small paws; the first six 
are attached in pairs on each side of the thorax or 
breast, and are called real and perfect ones, because 
they remain in the transformation from grub to 
nocturnal moth. These paws are scaly, articular, 
acuminated, and furnished with small talons. These 
paws serve the worm, not alone to move itself, but 
also as claws or arms to hold the leaves when gnaw- 
ing the same. Of the other ten paws, eight of them 
are attached in pairs, on the third, fourth, fifth, 
and sixth ring of the abdomen, and the other two 
are placed under the twelfth ring, or, more exactly, 
under the small wing-shaped projection which ter- 



36 The Silkworm. 

minates the body of the silkworm. These last two 
paws are less visible than the others, because they 
do not stand forth as the others do; but they are 
those on which the silkworm more often props itself, 
and by which it more easily fastens itself to objects. 

The silkworm does not respire or breathe through 
its nose or mouth, as do other animals, but their 
respiratory organs are placed along the length of 
their bodies, a little above where their paws are 
inserted, and are to be found in the first and second 
rings of the thorax or breast, and second, third, 
fourth, fifth, sixth, and eighth rings of the abdomen. 
There are eighteen of these breathing apparatus, 
nine on each side of the body. They are surrounded 
by thick, short hairs, and closed by a strong and 
rigid skin, in which are pores. The expiration of 
air from their bodies takes place through these pores. 
The silkworm changes its skin four times; and, it 
not only changes its skin, but also the covering of its 
head and the lining of trachea; also, a portion of 
the intestines, and all the organs which serve them 
to masticate with. 

When the silkworm is disposed to change its skin, 
or, more properly, is about to moult, little by little 
it loses its appetite, and then it ceases to eat; then it 
empties itself of all the material contained in its 
intestinal tubes; it moves about in search of a place 
where it may be comfortable and at its ease; it at- 
taches fasteners of very fine threads of silvery silk 



The Silkworm. 37 

around itself, or around the nibblings of the leaves, 
so that these threads may retain the old skin when 
the worm liberates itself from it; then it keeps its 
head raised up and immovable. During the time it 
remains in this position, little by little, a new skin 
and the horny part of the head is formed. The in- 
dication that the time for changing the skin is near 
is, that the three rings of the thorax or breast swell 
up in a manner to cover part of the head, so that 
it appears as though the head had grown larger. 
The color of the worm seems to be darker, which is 
accounted for by the old skin detaching itself from 
the new skin, and it no longer being united to the 
body of the animal, it becomes somewhat dry. 

When the head of the worm agitates lively, the 
skin on the head detaches itself like a mask; about 
the same time the six anterior paws creep forth from 
the old envelopment; finally, with a vermicular 
movement, the worm slowly creeps forth from its 
old skin, which it leaves behind him. This opera- 
tion becomes facilitated by the moisture which re- 
mains between the two skins. This moisture is not 
produced by any particular gland, but from the con- 
densation of the habitual transpiration; during the 
time the old skin becomes dead or less permeable at 
the time the worm is in a torpid state, this moisture 
condenses and produces a certain quantity of liquid 
which lubricates the parts that must glide over the 
other. The time occupied in changing the skin or 



38 The Silkworm. 

moulting is from twenty-four to thirty-six hours. 
It depends a great deal on the method of rearing 
the worms; also on the season being more or less 
favorable. 

The worm in its new skin appears to be smaller 
than before the change. The worm moves very 
slowly, as though still weak from the fatigue of 
moulting or shedding its skin. 

The silkworm is furnished with four senses, viz.: 
the touch, sight, smell, taste. The sense of touch— 
The silkworm gives signs of having that sense from 
the sensibility of its cuticle or skin, excepting in the 
first age, or stage, when it is less sensible on account 
of the thick long hairs with which it is covered. It 
also gives signs of suffering when wind or air is 
blown on it. 

The sight is shown by the position and simplicity 
of the eyes, which serve only to see a short distance; 
notwithstanding this, their eyes are as perfect as can 
be found in such insects. 

Smell — The silkworm gives signs of having this 
sense by moving its head towards the fresh leaves 
when administered to it; also, by passing over leaves 
that are not that of the mulberry. 

The taste sense, very pronounced, which serves 
them to select the food administered to them, as they 
refuse to eat that which is hurtful or not agreeable 
to them. 

The sense of hearing — Of this sense I should say 



The Silkworm. 



39 



they were almost deprived, as they seem to remain 
immovable when great noise is made about or near 
them. But as the senses of touch and smell are so 
exquisite in them, these supply the want of the sense 
of hearing. As the silkworm is an insect of cold 
blood, its temperature is about the same as the tem- 
perature in which it lives. It is- the contrary with 
the warm-blooded animals, who maintain their ordi- 
nary temperature independently from that of the 
atmosphere. 

The silkworm has blood, this being a fluid indis- 
pensable to the life of animals. Its color is more or 
less yellowish, varying from straw to orange color. 



C| (° °\ P 


GENERAL INSTRUCTIONS 

FOR 

REARING SILKWORMS, 

WITH A 

TREATISE OR SECURING HEALTHY SILKWORM EGGS, 

ALSO, A 

Sketch of the Habits and Structure of the Silkworm. 

By 
MRS. LOUISE RIENZI. 

* 

SACRAMENTO: 

STATE office, : : : : P. L. shoaff, supt. state printing. 

1887. 


* „,^~^ J vJ 




LIBRARY OF CONGRESS 



002 842 918 6 




vBEBBr 



